PTL 1 shows a structure in which a temperature measuring element is mounted on a sub air passage constituted by a part of a housing member, and a resin member constituting the sub-passage is formed with vent holes larger than the temperature measuring element on both side walls, and the temperature measuring element is disposed between the vent holes. In PTL 1, the temperature measuring element is installed at a position away from an electronic circuit board which drives the temperature measuring element.